ls2lp.m
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上传日期:2013-01-09
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- function [H,G,HT,GT] = ls2lp(LS,factMode)
- %LS2LP Lifting scheme to Laurent polynomials.
- % [H,G,HT,GT] = LS2LP(LS,FACTMODE) returns the two pairs of
- % Laurent polynomial associated to the lifting scheme LS.
- % The pairs (H,G), (HT,GT) are the primal and the dual pair
- % respectively. FACTMODE indicates the type of polyphase
- % matrix factorization. The valid values for FACTMODE are:
- % 'd' (dual factorization) or 'p' (primal factorization).
- %
- % LS2LP(LS) is equivalent to LS2LP(LS,'d').
- %
- % Let: [Hp,Gp,HTp,GTp] = LS2LP(LS,'p') and
- % [Hd,Gd,HTd,GTd] = LS2LP(LS,'d')
- %
- % If LS is associated to an orthogonal wavelet, then:
- % Hp = Hd , Gp = Gd , HTp = HTd , GTp = GTd
- %
- % If LS is associated to a biorthogonal wavelet, then:
- % Hp = HTd , Gp = GTd , HTp = Hd , GTp = Gd
- % M. Misiti, Y. Misiti, G. Oppenheim, J.M. Poggi 22-Jan-2003.
- % Last Revision: 27-Jun-2003.
- % Copyright 1995-2004 The MathWorks, Inc.
- % $Revision: 1.1.6.3 $ $Date: 2004/04/13 00:39:52 $
- if nargin<2 , factMode = 'd'; end
- PMF = ls2pmf(LS,factMode);
- PM = prod(PMF{:});
- Z = laurpoly(1,-1);
- PM = newvar(PM,'z^2');
- H = PM{1,1} + Z*PM{2,1};
- G = PM{1,2} + Z*PM{2,2};
- HT = -Z*newvar(newvar(G,'1/z'),'-z');
- GT = Z*newvar(newvar(H,'1/z'),'-z');
- %--------------------------------------
- % HT = -Z*modulate(reflect(G));
- % GT = Z*modulate(reflect(H));
- %--------------------------------------